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The synthesis and crystal structure of oxy-bridged bis(1 H -tetrazol-5-yl)furazan ( 2 ) were reported. The thermal behavior of 2 was investigated by DSC and TG–FTIR–MS coupling technique. The results showed that the thermolysis of 2 included two stages. The rupture of tetrazole ring occurred with the release of N 2 in the first stage. In the second stage, the striping of HCN from schiff base radical followed by the fragmentation of furazan ether moiety, which leading to the formation of N 2 O, NO and polymer. Furthermore, two decomposition pathways of 2 under electron impact condition were proposed, and the fracture of tetrazole ring and ether bond were considered as the initial step of molecule decomposition, respectively. [ABSTRACT FROM AUTHOR]

Ni(NH3)4(AFT)2 [NiC6H16N18O2, AFT = 4-amino-3-(5-tetrazolate)furazan] is synthesized and characterized by elemental analysis and Fourier-transform infrared spectroscopy for the first time. X-ray diffraction measurements are used to determine the crystal structure of compound 1. The results demonstrate that compound 1 crystallized in the orthorhombic crystal system. The nickel(II) ion is six-coordinated by N atoms from two AFT-ligands and four NH3 molecules. Its thermal properties are investigated by differential scanning calorimetry and thermogravimetry-derivative thermogravimetry methods, with the results demonstrating that the differential scanning calorimetry curve exhibits two endothermic and one exothermic processes. The endothermic processes are in the range of 130–510 °C with a peak temperature of 188 °C. The temperature from 230 to 400 °C is the exothermic process in which the peak temperature is 314.58 °C. In addition, Kissinger's and Ozawa-Doyle's methods are used for calculating the non-isothermal kinetics parameters. Moreover, the apparent activation energy (E), safety, and thermal stability parameters (T SADT, T TIT, T b) for Ni(NH3)4(AFT)2 are calculated. In addition, the calculated thermodynamic functions (∆S ≠, ∆H ≠, and ∆G ≠) for the exothermic decomposition process of Ni(NH3)4(AFT)2 are 55.07 J mol−1 K−1, 196.18 kJ mol−1, and 164.90 kJ mol−1, respectively. [ABSTRACT FROM AUTHOR]

In this study, 1-acetyl-3-(3-hydroxyphenyl)-5-(9-anthracenyl)-2-pyrazoline (AHAP) was synthesized and afforded two types of polymorphs. Single crystal X-ray analyses revealed that AHAP molecules connect with each other in a head-to-tail fashion through O-H⋯O hydrogen bonds between the carbonyl and hydroxyl groups. However, through the above intermolecular interactions and stacking mode, the one-dimensional chain motifs are formed in the α polymorph and cyclic tetramers are formed in the β polymorph, which constitute their crystal structures as units. Compared with solvent-free α polymorph, the unit cell of the β polymorph includes a small region of disordered solvent molecules. CrystalExplorer program, Differential scanning calorimetry (DSC) and thermogravimetric thermal analysis (TGA) experiments revealed that the voids should be inside the tetramers and each void contains one disordered solvent molecule. 1H NMR spectra conformed the type of the disordered solvent molecule is consistent with the crystalline liquid phase. The optical-physical properties of the two polymorphs were also investigated. They emit similar fluorescence, which is assigned to monomer emission of anthracene, due to the monomer arrangement of anthracene fluorophores in the two polymorphs. Image 1 • The identical O-H⋯O hydrogen bonds induced polymorphism of pyrazoline derivative. • High stability of the two polymorphs due to the strong hydrogen bonds. • One-dimensional chain motifs and tetramer structure formed by hydrogen bonds, respectively. [ABSTRACT FROM AUTHOR]

A new energetic zinc-FOX-7 complex (FOX-7 = 1,1-diamino-2,2-dinitroethylene), Zn(NH3)2(FOX-7)2, was synthesized and structurally characterized by single crystal X-ray diffraction. Zn2+was coordinated by four nitrogens from two ammonias and two FOX-7?anions, forming a distorted tetrahedron. Thermal decomposition of Zn(NH3)2(FOX-7)2was studied by differential scanning calorimetry and thermogravimetry/differential thermogravimetry. The apparent activation energy and pre-exponential constant of the first decomposition process are 144.8 kJ M?1and 1013.99?s?1, respectively. The self-accelerating decomposition temperature and critical temperature of thermal explosion of Zn(NH3)2(FOX-7)2are 183.2 and 195.8?°C, respectively. The thermal stability of Zn(NH3)2(FOX-7)2is good, but Zn(NH3)2(FOX-7)2is still sensitive. [ABSTRACT FROM PUBLISHER]